Topic: Tapioca Manihot esculenta Crantz.

TAPIOCA (Cassava) : Manihot esculenta Crantz.

Chromosome No : (2n = 2x = 36) Family: Euphorbiaceae

Origin:North-Eastern Brazil Economic part of this plant are roots or tubers. Starch content in

cassava is highest among other tuber crops i.e. (25-40 %) Tubers also contain a deadly poisonous chemical i.e. HCN. Upon sun drying cyanide derivatives disappear from slices of cassava.

Nigeria, Ghana, Brazil, Thailand, Indonesia and India are the major growing country in world.

In India crop is cultivated in southern peninsular region, particularly in Kerala, Tamil Nadu and Andhra Pradesh contributing 93% of area and 98% of production in the country. Area under Tapioaca in India is 207.59(000ha) and production is 4372.68(000MT)

Kerala accounts for nearly 50% of total area under cassava in India and is mainly grown as rainfed crop.

NHB (2014-15)

Area and Production

It is a perennial shrub producing 5-10 cylindrical tubers per plant.

The stem is woody and variously branched. Two distinct types are present – one without branching at the top and the other with spreading nature.

Cassava is monoecious in nature and cross-pollinated. Female flowers are fewer in numbers and borne in the base of inflorescence. Female flowers open about 10 days before male flower anthesis.

Tubers are composed of a thin peridium, white or purple cortex known as rind and Central massive flesh rich in starch (25-40%).

Botany

Most of the crop improvement works on cassava are done at the Central Tuber Crops Research Institute (CTCRI), Thrivendrum.

Sree Sahya: This is a non-branching and multiple hybrid involving five parents, tubers are long and rind is cream coloured; yield 35-40t/ha in 10-11 months.

Sree Prakash: This is a short, non-branching, early maturing (7-8 months) variety developed by clonal selection; highly tolerant to Cercospora leaf spot; yield 35-40 t/ha .

Varieties

Sree Harsha: This is a triploid clone developed by crossing a diploid with an induced tetraploid clone of ‘Sree Sahya’; plants are erect and non-branching with tubers of good cooking quality and high starch content (38-41%); yield 35-40 t/ha in 7-8 months.

Sree Jaya and Sree Vijaya : These are short-duration (6 months) clonal selection suitable for low land cultivation as a rotation crop in paddy-based inter-cropping system; tubers are with brown skin and purple rind and have good cooking quality; yield 26-30 t/ha; susceptible to CMD.

 H-97, H-165 and H-226 are important hybrids.Sree Rekha, Sree Prabha, Nidhi ,CO-1 are new varieties.

Cont…

Variety Pedigree Duration (days)

Yield(t/ha)

Starch content(%)

Source

H-97 Manjuvella×brazilian seedling

260-300 25-35 27-29 CTCRI

H165 Chadyamangalam vella×clone similar to kalkalan

220-240 33-38 23-25 CTCRI

H226 Ethakka karuppan×M-4(Malaysia)

260-300 30-35 28-30 CTCRI

Sree Visakham(H-1687)

Ac. No.1501 local×S-2312 270-300 35-38 25-27 CTCRI

Sree Prakash Selection from local accessions

210-240 35-40 29-31 CTCRI

Sree Harsha Triploid 270-300 35-40 29-31 CTCRI

CO1 Clonal selection from atype of Tiruchi

260-275 30-35 TNAU

Variety Pedigree Duration(days)

Yield(t/ha) Starch content(%)

Source

CO2 Open pollinated seedling from Thiruvarur type, Tanjore

260-275 30-35 _ TNAU Coimbtore

CO3 Selection from OP seeds from IITA, Nigeria

240-270 35-40 _ TNAU Coimbtore

Vellyani Hrsawa

Clonal selection 155-180 43 _ KAU, vellanikkara

Climate: Cassava is a tropical crop tolerant to drought and can not withstand frost. It is grown in altitudes up to 2000 m, but performance is better in lower

altitudes. Though crop can be grown even in semi-arid conditions, growth and

productivity are better in warm humid climate with well distributed rainfall (2000mm) annual rainfall .

Soil: Cassava grows on all types of soils, but saline, alkaline and ill-drained

soils are not suitable. Red sandy loam is mostly preferred with pH ranging from 6.5-8.

It is relatively a drought tolerant crop. Cassava can recover from the damage of slight moisture stress of shorter duration (short day plant).

Crop is mainly grown in laterite soils in Kerala and black and red soils in Tamil Nadu.

Planting season : As an irrigated crop, cassava can be planted during any part

of year, but December-January planting is better. As a rainfed crop, planting is done during April-May before

onset monsoon.

Propagation Stem cuttings, usually called as sets, for planting are taken

from disease free stakes of 8-10 months maturity having a thickness of 2-3 cm diameter.

Discard woody basal portion and tender top portion of stem. Prepare sets of 15-20 cm length with a smooth circular cut at the base and slanting cut at top for easy identification of base and top. Sets prepared from stem stored for 15 days with leaves give better sprouting.

Ideals sets

Ready for transplanting

Planting: Wider spacing of 90 x 90 cm is recommended for branching types

(H- 97 variety). Narrow space of 75 x 75 cm is for non-branching types (H-165 variety).

Two shoots per hill is found to be the best practice. Planted by horizontal or vertical planting method.

Cassava sticks can be planted at 45 degree angle or vertically. Always put the sticks lower end in the ground.

Manuring: Cassava is a heavy feeder and crop is to be adequately manures

for getting high yield. Apply 125 tonnes of farmyard manure / ha as basal dose. A

fertilizer dose of 50 kg N, 50 kg P and 50 kg K / ha is recommended at the time of land preparation.

Interculture: Pinching off excess sprouts emerging from sets is necessary in

cassava cultivation. This may be done 30-45 days after planting.

First inter-culture operation may be done sufficiently deep at 45-60 days after planting and a shallow inter-culture by way of weeding or earthling up may be given one month after the first.

Irrigating crop at 25% available moisture depletion level, could double tuber yield compared to irrigated crop.

Irrigation: Water stress condition should be avoided as it is harmful to the crop. In the irrigated crop, irrigation is given at 10-15days interval.

Harvesting and yield: The crop is ready for harvesting in 10-11 months after

planting. Short duration varieties can be harvested in 6-7 months.

Delayed harvest results in deterioration of quality of tubers. Harvesting is usually done by uprooting plants gently by holding stem. After harvesting, stack stems vertically in well aerated place for use in subsequent planting.

Yield is 25-30 t/ha for short duration varieties and 30-40 t/ha for other varieties.

  Diseases:Brown leaf spot (Cercospora henningsi)- It is serious disease in heavy

rainfall areas. Control- Spray the crop with 0.1% benlate. Cassava bacterial blight (Xanthomonas manihotis)- This disease is

characterized by the appearance of leaf spots, blight, wilting, gum exudation and vascular necrosis of plants.

Control- Grow resistant varieties, select healthy and disease free planting material.

Cassava mosaic disease (CMD) - The chlorotic specks appear on the leaves, which turn bright yellow and finally cover the whole leaf lamina. It is transmitted through white fly.

Control- Spray either dimethoate or monocrotophos at 0.03%.

Tuber rot (Phytophthora drechsleri)- Internal tissues of tubers discoloured brown with foul smell and rot.

Control: remove infected tubers from the field and incorporate Trichoderma viridae into soil.

Proper drainage.

INSECT-PESTS :Soft scale (Aonidomytellus albus)- Stems become weak and dry due to

white scale colonies, side branching with bushy appearnce. infested plants have poor vaibility.

Control- Use scale free stem for planting, allow the setts in 0.05% solution of Dimethoate for 10 minutes, spray malathion(0.1%) or methyl parathion(0.05%). 

Stem borer (Pterolophia melanura and Sybra praeusta)- Control- Apply carbofuran 3G or phorate 10G @20-25kg/ha in soil before

planting, spray carbaryl (0.1%).

Thrips (Retithrips syriacus) leaves turn pale , roll and dry up. Spray Dimethoate(0.05%) White fly (Bemisia tubaci) It is the vector transmitting Indian cassava

moasic virus. Its control will check the spread of disease. Spray Dimethoate(0.05%)

Spiral white fly (Aleurodicus dispersus)Yellowish speckels, crinkling and curling of leaves snd black sooty

mould in svere cases.Spray Azadirachtin or any other neem based insecticide.

Red spider mite (Tetranychus telarius)- Control- Dimethoate or methyl demeton (0.05%), monocrotophos

(0.03%).

Root-knot nematode (Meloidogyne incognita or javanica or arenaria)-

Control- Give deep summer ploughing, follows crop rotation with resistant crops, grow resistant var.

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